Drench showers & eye/face washes
How to prevent human error misuse
While lack of knowledge about proper usage is sometimes the cause of misuse, rushing and taking shortcuts are often the culprit. Either way, safety and facility managers can head off dangerous misuse of eye/face washes and drench showers by anticipating these mistakes and building a strong safety net to ensure compliance with ANSI requirements, and proper preparation and usage.
Here are some common areas prone to mishandling that should be reinforced in industrial facilities:
Re-evaluating job sites for equipment needs
Job-site evaluations should not be a one-time event — as with training, testing and maintenance of emergency fixtures. Since work environments are dynamic and change over time, assessments should be conducted annually to ensure the proper type, quantity and location of emergency fixtures. Some emergency equipment manufacturers offer free job-site evaluations and can be instrumental in assessing potential problems.
During a walk-through, it is essential to reference the American National Standards Institute (ANSI) Z358.1—2009 emergency equipment standard, which outlines the specific requirements for emergency eyewash and drench shower equipment installation, testing, performance, maintenance, training and use. Safety Data Sheets (SDS) are another excellent starting point to determining protection needs, as they contain the first aid information indicating if drenching facilities are required.
Too often, facilities managers underestimate the maximum distance allowed between a critical work area and eyewash/safety shower product. ANSI provides the following guidelines for product placement:
• A drench shower, eyewash or combination unit should be located within 10 seconds of any worker at risk for chemical exposure. The distance a worker can travel in this time frame is estimated to be 55 feet.
• The equipment must be on the same level on which the user is working. If there are doors between the hazard and the fixture, they must swing in the direction of travel.
• If the worker’s ability to walk or move might be impacted by the chemical exposure, the fixture should be placed closer to the worker.
• If highly corrosive chemicals are used, the drench shower or eyewash should be placed immediately adjacent to the hazard.
• If a potential chemical spill in an area is likely to affect multiple workers, a sufficient number of fixtures should be in place to prevent one worker from having to wait 15 minutes while another is drenched.
It’s also important for safety fixtures to be clearly identifiable and easy to reach:
• The area around the fixture should be well-lighted.
• Each fixture should be identified with a highly visible sign.
• A drench shower or eyewash in a bright color like yellow is easiest to spot in a busy industrial environment.
• Eyewash sprayheads should be a minimum of 6 inches from walls or obstructions to allow the user clear access for eye flushing.
• The area for flushing under the drench shower should be unobstructed. The only exception is the eyewash on a combination drench shower and eyewash fixture. In this case, the eyewash is placed in line with the drench shower to allow for simultaneous use.
Ensuring correct water temperature and pressure
Another common error with eye/face washes and drench showers is failing to provide tepid water. ANSI Z358.1 requires that tepid water be delivered to emergency fixtures, which encourages an injured party to complete the full 15-minute flush during an emergency. ANSI suggests an incoming water temperature between 60° F and 100° F.
Oftentimes maintaining tepid water is overlooked — mostly due to cost — and some take for granted that cold water will be sufficient. However, if the water is below 60° F, prolonged exposure could cause hypothermia. Most often, cold water will cause the user to leave the drench or rinse before the 15-minute guideline, risking bodily damage.
Water supply to the unit must also be sufficient to support a full 15-minute flow of flushing fluid. For both drench showers and eyewashes, a minimum water pressure of 30 pounds per square inch (PSI) should be supplied to the unit. It must also satisfy the ANSI minimum flow rate, which is at least 20 gallons per minute (GPM) for drench showers, 0.4 GPM for eyewashes and 3.0 GPM for eye and face washes. Actual flow rates vary by product, so consult with the equipment manufacturer to verify flow rates.
For some, in a pinch, supplemental products can provide a source of quick, immediate relief, but they cannot replace the greater need for a full 15-minute rinse with tepid water. Every potential hazard should be supported by a plumbed or portable device that has access to an adequate water supply at an appropriate pressure and temperature.
Selecting TMVs and tankless water heaters
Thermostatic mixing valves (TMVs) blend hot and cold water to a specific setpoint and are an effective solution for delivering tempered water to emergency fixtures, as are specially designed on-demand water heaters. Both technologies help ensure that the user will stay in the water rinse for the full 15 minutes.
If the tempering design involves the selection of a TMV, it’s important to select a valve that is an emergency thermostatic mixing valve and not a standard valve. Emergency TMVs are specifically designed to allow for a continuous free flow of cold water if the hot water supply runs out or is interrupted.
There are new tankless heating systems that are especially efficient and precise in supplying tepid water at a second’s notice for use in drench shower and eyewash systems, as they contain additional safeguards to prevent scalding of an injured worker. Newer models draw energy only when needed, hold outlet temperature to within ± 1° F, and have a low pressure drop (10–12 pounds per square inch). Systems with this capacity will minimize potential post-installation complications due to a sudden pressure drop, resulting in minimal pressure at the fixture.
It is all too common to improperly size a tankless water heater: While most look only at the average ground water temperature, the product needs to
be configured based on the lowest ground water temperature.
Consulting with a third-party safety consultant and/or an emergency equipment product manufacturer can help managers formulate a solid safety plan involving plumbed emergency fixtures. When dealing with the health and safety of employees, knowing that proper emergency fixtures are correctly installed and prepared will promote valuable peace of mind for all.